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<div class="title">hello.c File Reference</div>  </div>
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<div class="textblock"><code>#include &lt;<a class="el" href="fuse_8h_source.html">fuse.h</a>&gt;</code><br />
<code>#include &lt;stdio.h&gt;</code><br />
<code>#include &lt;string.h&gt;</code><br />
<code>#include &lt;errno.h&gt;</code><br />
<code>#include &lt;fcntl.h&gt;</code><br />
<code>#include &lt;stddef.h&gt;</code><br />
<code>#include &lt;assert.h&gt;</code><br />
</div>
<p><a href="hello_8c_source.html">Go to the source code of this file.</a></p>
<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<div class="textblock"><p>minimal example filesystem using high-level API</p>
<p>Compile with: </p><pre class="fragment">gcc -Wall hello.c `pkg-config fuse3 --cflags --libs` -o hello
</pre><h2>Source code</h2>
<div class="fragment"><div class="line"><span class="comment">/*</span></div><div class="line"><span class="comment">  FUSE: Filesystem in Userspace</span></div><div class="line"><span class="comment">  Copyright (C) 2001-2007  Miklos Szeredi &lt;miklos@szeredi.hu&gt;</span></div><div class="line"><span class="comment"></span></div><div class="line"><span class="comment">  This program can be distributed under the terms of the GNU GPL.</span></div><div class="line"><span class="comment">  See the file COPYING.</span></div><div class="line"><span class="comment">*/</span></div><div class="line"></div><div class="line"><span class="preprocessor">#define FUSE_USE_VERSION 31</span></div><div class="line"></div><div class="line"><span class="preprocessor">#include &lt;<a class="code" href="fuse_8h.html">fuse.h</a>&gt;</span></div><div class="line"><span class="preprocessor">#include &lt;stdio.h&gt;</span></div><div class="line"><span class="preprocessor">#include &lt;string.h&gt;</span></div><div class="line"><span class="preprocessor">#include &lt;errno.h&gt;</span></div><div class="line"><span class="preprocessor">#include &lt;fcntl.h&gt;</span></div><div class="line"><span class="preprocessor">#include &lt;stddef.h&gt;</span></div><div class="line"><span class="preprocessor">#include &lt;assert.h&gt;</span></div><div class="line"></div><div class="line"><span class="comment">/*</span></div><div class="line"><span class="comment"> * Command line options</span></div><div class="line"><span class="comment"> *</span></div><div class="line"><span class="comment"> * We can&#39;t set default values for the char* fields here because</span></div><div class="line"><span class="comment"> * fuse_opt_parse would attempt to free() them when the user specifies</span></div><div class="line"><span class="comment"> * different values on the command line.</span></div><div class="line"><span class="comment"> */</span></div><div class="line"><span class="keyword">static</span> <span class="keyword">struct </span>options {</div><div class="line">        <span class="keyword">const</span> <span class="keywordtype">char</span> *filename;</div><div class="line">        <span class="keyword">const</span> <span class="keywordtype">char</span> *contents;</div><div class="line">        <span class="keywordtype">int</span> show_help;</div><div class="line">} options;</div><div class="line"></div><div class="line"><span class="preprocessor">#define OPTION(t, p)                           \</span></div><div class="line"><span class="preprocessor">    { t, offsetof(struct options, p), 1 }</span></div><div class="line"><span class="keyword">static</span> <span class="keyword">const</span> <span class="keyword">struct </span><a class="code" href="structfuse__opt.html">fuse_opt</a> option_spec[] = {</div><div class="line">        OPTION(<span class="stringliteral">&quot;--name=%s&quot;</span>, filename),</div><div class="line">        OPTION(<span class="stringliteral">&quot;--contents=%s&quot;</span>, contents),</div><div class="line">        OPTION(<span class="stringliteral">&quot;-h&quot;</span>, show_help),</div><div class="line">        OPTION(<span class="stringliteral">&quot;--help&quot;</span>, show_help),</div><div class="line">        <a class="code" href="fuse__opt_8h.html#aca35962e17d189ceb5447f8eea11bd33">FUSE_OPT_END</a></div><div class="line">};</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span> *hello_init(<span class="keyword">struct</span> <a class="code" href="structfuse__conn__info.html">fuse_conn_info</a> *conn,</div><div class="line">                        <span class="keyword">struct</span> <a class="code" href="structfuse__config.html">fuse_config</a> *cfg)</div><div class="line">{</div><div class="line">        (void) conn;</div><div class="line">        cfg-&gt;<a class="code" href="structfuse__config.html#ac055a1643c6c7aa7fb19341cf7f39aad">kernel_cache</a> = 1;</div><div class="line">        <span class="keywordflow">return</span> NULL;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">int</span> hello_getattr(<span class="keyword">const</span> <span class="keywordtype">char</span> *path, <span class="keyword">struct</span> stat *stbuf,</div><div class="line">                         <span class="keyword">struct</span> <a class="code" href="structfuse__file__info.html">fuse_file_info</a> *fi)</div><div class="line">{</div><div class="line">        (void) fi;</div><div class="line">        <span class="keywordtype">int</span> res = 0;</div><div class="line"></div><div class="line">        memset(stbuf, 0, <span class="keyword">sizeof</span>(<span class="keyword">struct</span> stat));</div><div class="line">        <span class="keywordflow">if</span> (strcmp(path, <span class="stringliteral">&quot;/&quot;</span>) == 0) {</div><div class="line">                stbuf-&gt;st_mode = S_IFDIR | 0755;</div><div class="line">                stbuf-&gt;st_nlink = 2;</div><div class="line">        } <span class="keywordflow">else</span> <span class="keywordflow">if</span> (strcmp(path+1, options.filename) == 0) {</div><div class="line">                stbuf-&gt;st_mode = S_IFREG | 0444;</div><div class="line">                stbuf-&gt;st_nlink = 1;</div><div class="line">                stbuf-&gt;st_size = strlen(options.contents);</div><div class="line">        } <span class="keywordflow">else</span></div><div class="line">                res = -ENOENT;</div><div class="line"></div><div class="line">        <span class="keywordflow">return</span> res;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">int</span> hello_readdir(<span class="keyword">const</span> <span class="keywordtype">char</span> *path, <span class="keywordtype">void</span> *buf, <a class="code" href="fuse_8h.html#a7dd132de66a5cc2add2a4eff5d435660">fuse_fill_dir_t</a> filler,</div><div class="line">                         off_t offset, <span class="keyword">struct</span> <a class="code" href="structfuse__file__info.html">fuse_file_info</a> *fi,</div><div class="line">                         <span class="keyword">enum</span> <a class="code" href="fuse_8h.html#af2bcf2a473b41b3cc8da8c079656a074">fuse_readdir_flags</a> flags)</div><div class="line">{</div><div class="line">        (void) offset;</div><div class="line">        (void) fi;</div><div class="line">        (void) flags;</div><div class="line"></div><div class="line">        <span class="keywordflow">if</span> (strcmp(path, <span class="stringliteral">&quot;/&quot;</span>) != 0)</div><div class="line">                <span class="keywordflow">return</span> -ENOENT;</div><div class="line"></div><div class="line">        filler(buf, <span class="stringliteral">&quot;.&quot;</span>, NULL, 0, 0);</div><div class="line">        filler(buf, <span class="stringliteral">&quot;..&quot;</span>, NULL, 0, 0);</div><div class="line">        filler(buf, options.filename, NULL, 0, 0);</div><div class="line"></div><div class="line">        <span class="keywordflow">return</span> 0;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">int</span> hello_open(<span class="keyword">const</span> <span class="keywordtype">char</span> *path, <span class="keyword">struct</span> <a class="code" href="structfuse__file__info.html">fuse_file_info</a> *fi)</div><div class="line">{</div><div class="line">        <span class="keywordflow">if</span> (strcmp(path+1, options.filename) != 0)</div><div class="line">                <span class="keywordflow">return</span> -ENOENT;</div><div class="line"></div><div class="line">        <span class="keywordflow">if</span> ((fi-&gt;<a class="code" href="structfuse__file__info.html#ae7d31802727be19670193a411647bca5">flags</a> &amp; O_ACCMODE) != O_RDONLY)</div><div class="line">                <span class="keywordflow">return</span> -EACCES;</div><div class="line"></div><div class="line">        <span class="keywordflow">return</span> 0;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">int</span> hello_read(<span class="keyword">const</span> <span class="keywordtype">char</span> *path, <span class="keywordtype">char</span> *buf, <span class="keywordtype">size_t</span> size, off_t offset,</div><div class="line">                      <span class="keyword">struct</span> <a class="code" href="structfuse__file__info.html">fuse_file_info</a> *fi)</div><div class="line">{</div><div class="line">        <span class="keywordtype">size_t</span> len;</div><div class="line">        (void) fi;</div><div class="line">        <span class="keywordflow">if</span>(strcmp(path+1, options.filename) != 0)</div><div class="line">                <span class="keywordflow">return</span> -ENOENT;</div><div class="line"></div><div class="line">        len = strlen(options.contents);</div><div class="line">        <span class="keywordflow">if</span> (offset &lt; len) {</div><div class="line">                <span class="keywordflow">if</span> (offset + size &gt; len)</div><div class="line">                        size = len - <a class="code" href="structfuse__opt.html#a333dcd849a3bd54df06084a69b5a8d39">offset</a>;</div><div class="line">                memcpy(buf, options.contents + offset, size);</div><div class="line">        } <span class="keywordflow">else</span></div><div class="line">                size = 0;</div><div class="line"></div><div class="line">        <span class="keywordflow">return</span> size;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keyword">struct </span><a class="code" href="structfuse__operations.html">fuse_operations</a> hello_oper = {</div><div class="line">        .<a class="code" href="structfuse__operations.html#a0ad1f7c4105ee062528c767da88060f0">init</a>           = hello_init,</div><div class="line">        .getattr        = hello_getattr,</div><div class="line">        .readdir        = hello_readdir,</div><div class="line">        .open           = hello_open,</div><div class="line">        .read           = hello_read,</div><div class="line">};</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span> show_help(<span class="keyword">const</span> <span class="keywordtype">char</span> *progname)</div><div class="line">{</div><div class="line">        printf(<span class="stringliteral">&quot;usage: %s [options] &lt;mountpoint&gt;\n\n&quot;</span>, progname);</div><div class="line">        printf(<span class="stringliteral">&quot;File-system specific options:\n&quot;</span></div><div class="line">               <span class="stringliteral">&quot;    --name=&lt;s&gt;          Name of the \&quot;hello\&quot; file\n&quot;</span></div><div class="line">               <span class="stringliteral">&quot;                        (default: \&quot;hello\&quot;)\n&quot;</span></div><div class="line">               <span class="stringliteral">&quot;    --contents=&lt;s&gt;      Contents \&quot;hello\&quot; file\n&quot;</span></div><div class="line">               <span class="stringliteral">&quot;                        (default \&quot;Hello, World!\\n\&quot;)\n&quot;</span></div><div class="line">               <span class="stringliteral">&quot;\n&quot;</span>);</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keywordtype">int</span> main(<span class="keywordtype">int</span> argc, <span class="keywordtype">char</span> *argv[])</div><div class="line">{</div><div class="line">        <span class="keywordtype">int</span> ret;</div><div class="line">        <span class="keyword">struct </span><a class="code" href="structfuse__args.html">fuse_args</a> args = <a class="code" href="fuse__opt_8h.html#a9bea40fe56b18be9aa110185ab7387ed">FUSE_ARGS_INIT</a>(argc, argv);</div><div class="line"></div><div class="line">        <span class="comment">/* Set defaults -- we have to use strdup so that</span></div><div class="line"><span class="comment">           fuse_opt_parse can free the defaults if other</span></div><div class="line"><span class="comment">           values are specified */</span></div><div class="line">        options.filename = strdup(<span class="stringliteral">&quot;hello&quot;</span>);</div><div class="line">        options.contents = strdup(<span class="stringliteral">&quot;Hello World!\n&quot;</span>);</div><div class="line"></div><div class="line">        <span class="comment">/* Parse options */</span></div><div class="line">        <span class="keywordflow">if</span> (<a class="code" href="fuse__opt_8h.html#a539ef1f571c34f516c60c4cbe2901c0e">fuse_opt_parse</a>(&amp;args, &amp;options, option_spec, NULL) == -1)</div><div class="line">                <span class="keywordflow">return</span> 1;</div><div class="line"></div><div class="line">        <span class="comment">/* When --help is specified, first print our own file-system</span></div><div class="line"><span class="comment">           specific help text, then signal fuse_main to show</span></div><div class="line"><span class="comment">           additional help (by adding `--help` to the options again)</span></div><div class="line"><span class="comment">           without usage: line (by setting argv[0] to the empty</span></div><div class="line"><span class="comment">           string) */</span></div><div class="line">        <span class="keywordflow">if</span> (options.show_help) {</div><div class="line">                show_help(argv[0]);</div><div class="line">                assert(<a class="code" href="fuse__opt_8h.html#a21602e6a0fff64fc9c7b642d12382094">fuse_opt_add_arg</a>(&amp;args, <span class="stringliteral">&quot;--help&quot;</span>) == 0);</div><div class="line">                args.<a class="code" href="structfuse__args.html#a6f90bec2356aff03de79baaca65276b6">argv</a>[0][0] = <span class="charliteral">&#39;\0&#39;</span>;</div><div class="line">        }</div><div class="line"></div><div class="line">        ret = <a class="code" href="fuse_8h.html#ac99b844cee7aaa8fb4e35df5b5488d82">fuse_main</a>(args.<a class="code" href="structfuse__args.html#a501883d1eababa08e05b0c802b31e11d">argc</a>, args.<a class="code" href="structfuse__args.html#a6f90bec2356aff03de79baaca65276b6">argv</a>, &amp;hello_oper, NULL);</div><div class="line">        <a class="code" href="fuse__opt_8h.html#a2cdf272429ab3869a5162976141b287d">fuse_opt_free_args</a>(&amp;args);</div><div class="line">        <span class="keywordflow">return</span> ret;</div><div class="line">}</div></div><!-- fragment --> 
<p class="definition">Definition in file <a class="el" href="hello_8c_source.html">hello.c</a>.</p>
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